Microblogging network Tumblr (s yhoo) was arguably the highest-profile acquisition made by Yahoo under CEO Marissa Mayer. So how are things going one year in? Tumblr founder and CEO David Karp told the New York Times that he doesn’t regret the decision — Yahoo has kept to its word and let the company operate independently. However, Karp also admitted that the support from its new parent company hasn’t helped Tumblr solve its problems generating revenue. While Tumblr is exploring Yahoo’s ad technology in earnest, the money has yet to roll in — even as the company continues to grow its already-doubled staff.